Moistening apparatus



March 8, 1949. F. c. DAWSON MOISTENING APPARATUS Filed Jan. '7, 1947 3 Sheets-Sheet l INVENTOR.

F "ec C. DawsOZ Mmh s, 1949. F. c. bAWSON 2,464,119

MOI STENING APPARATUS Filed Jan. 7, 1947 3 Sheets-Sheet 2 I N VEN TOR.

red C D w 'z BY W \7 W March 8, E949. F. c. DAWSON 2,4643% MOI STENING APPARATUS 3 Sheets-Sheet 3 Filed Jan' 7, 1947 INVENTOR. Fred C. 004060 7 AT/Drhey Patented Mar. 8, 1949 UNITED STATES PATENT OFFICE MOISTENING APPARATUS Fred C. Dawson, Canton, Mass.

Application January 7, 1947, Serial No. 720,664

4 Claims. (01. 34-155) This invention relates to the moistening of sheet material such, for example, as paper, and relates more particularly to the setting of moisture setting ink which has been printed upon sheets or webs, such as paper.

Moisture setting inks are preferred for printing on the paper used for the packaging of foods, for example, for the reason that the odors and tastes which result from other inks, are not present, and the colors which may be used are more natural and pleasing to the eye. Since, however, the coloring matter in water setting ink requires moisture for its precipitation on the printed surface, the usual dryers using heat for the evaporation of the ink solvent cannot be used for speeding up the setting of the ink without damaging the ink or the paper upon which it is printed.

This invention provides for the supply of controlled quantities of moisture to sheet or web material, and provides in the printing field, for the quick setting of moisture setting inks, which utilizing this invention, can be printed upon sheets of paper such as used for the packaging of foods, cigarettes and other articles, and for other purposes, and in which the setting is completed without damage to the ink or the surface upon which it is printed.

In one embodiment of apparatus for the practice of the invention, low pressure steam is projected through one or more transverse slits upon the surface of a moving web. or sheet on which is printed the ink to be set, and the steam together with air from adjacent the apparatus, is drawn into a hood and exhausted.

A feature of the invention is that the low pressure steam is maintained at the proper humidity, preferably by controlling the super-heat added by steam at a higher pressure in a pipe extending around the pipe supplying the low pressure steam to each slit.

Another feature of the invention is that the steam and the air drawn into the exhaust hood is maintained at temperatures above their dew point temperatures so that no moisture can condense and fall back upon the paper.

An object of the invention is to apply accurately controlled quantities of moisture to the surfaces of sheet or web materials.

Another object of the invention is to speed up the setting of moisture setting inks printed upon the sheet or web materials.

The invention will now be described with reference to the drawing, of which:

Fig. 1 is a plan view looking downwardly upon an ink setting unit embodying this invention;

Figb2 is a side elevation of the unit;

Fig. 3 is a sectional view along the lines 3-3 of Fig. 1;

Fig. 4 is a sectional view along the lines 4-4 of Fig. 1;

Fig. 5 is an end elevation of a portion of the unit, and

Fig. 6 is an enlarged cross-sectional view of one of the low pressure steam slits, the pipe supplying steam thereto, and the pipe supplying steam for superheating the low pressure steam.

The essence of the invention as applied to the setting of moisture setting inks, can most readily be understood with reference to Fig. 4 in which the paper sheet H) which previously has been printed with moisture setting ink is continuously moved by conventional apparatus which is not illustrated, from right to left facing'Fig. 4 of the drawing through the unit 9. Low pressure steam from which excess moisture has been removed as will be described, is supplied through the transversely extending, inner pipes l I and through the nozzle slits 52 formed in the lower portions of the pipes, onto the upper surface of the sheet if]. The slits l2 extend across the entire width of the sheet l6 and projects low pressure steam at a relatively high velocity upon the sheet. Steam at a higher pressure is supplied into the relatiglely large pipes i3 extending around the pipes l The purpose of the steam in the pipes I3 is to add superheat to the steam in the pipes l I so that the steam passing through the slits l2 onto the sheet I0 is maintained at the proper'humidity. For example, it may be maintained at a point Just on the dry side of saturation. Upon contacting the cooler paper it is cooled to its saturation temperature or slightly below sam whereby the proper quantity of moisture required for setting the ink is condensed upon the paper surface. A large excess of moisture over that required for setting the ink is not required since it would result in unnecessary steam consumption and in undesired moisture on the surface of the paper leaving the unit.

By way of example, if the paper is printed, the steam pressure in the pipes l3 may be 18-20 pounds while the steam pressure in the pipes ll may be 10 inches water gauge. If the .paper is 2% printed, the steam pressure in the pipes may be 5 pounds and the steam pressure in the pipe II may be 2 inches water gauge. As is apparent, larger steam volume and therefore higher pressures are required when the percentage of printing is greater.

The sheet metal member l4 encloses the heat insulating member l5, and forms the enclosure 2| which extends over the pipes l3, and down along the outer sides thereof to levels just above the slits [2. The sheet metal hood wall I6 is in contact with the outer surface of the member I4, and has the sheet metal hood wall I! spaced therefrom and forming therebetween, the exhaust hood passage H! which connects with the .outlet duct l9 which is adapted to be connected to the inlet of an exhaust fan which is not illustrated.

The lower ends of the walls 16 and I! are spaced apart to form the slots 20 therebetween, through which the steam from the slits l2, and air from the apparatus room is drawn. The steam pipes 22 are supported by the brackets 23 at each end of the hood on opposite sides of the slots 20 and adjacent the inner ends of the enclosure formed by the member M, and are supplied with high pressure steam as will be described. The pipes 22 are heated by the high pressure steam supplied thereto and serve to heat the steam, and the air entering the slots 20 for maintaining same above the dew point of the mixture whereby no liquid droplets can condense and fall back upon the paper.

The insulation 15 is provided for preventing the inner surface of the member l4 forming the enclosure 2| from being chilled below the dew point of the steam thus preventing condensation of moisture which might drop upon the sheet [0.

The steam piping to the pipes I l, 13 and 22 will now be described with reference to Figs. 1, 2 and 6. Steam from a suitable source is supplied through the pipe 30, the valve 3| and the pipe 32 directly to the pipes 22. The pipe also supplies steam through the conventional Centrifix 34 which serves to remove excess moisture from the steam, and from the Centrifix through the pressure reducing valve 36, the solenoid operated valve 35 and the piping 31 to the steam pipes H. Steam from the Centrifix is also supplied through the pressure reducing valve 38 and piping 39 to the steam pipes l3.

The valves 36 and 38 have the hand wheels 40 and M respectively which are adjusted when the percentage of printing on the paper changes, the valve 36 providing the necessary steam volume through the slits l2 for setting the ink, and the valve 38 providing the necessary steam pressure in the pipes [3 for maintaining the setting steam just on the super-heat side of saturation.

The pressure of the steam supplied into the pipes 22 is not critical, and full line pressure can be used, since the purpose of these pipes is to add suificient heat to the mixed air and steam entering the exhaust passage to prevent the mixture from being cooled below its dew point temperature.

The lower portions of the pipes I3 are connected through the pipes to the inlet of the conventional condensate trap 46, the pipe 41 connecting the outlet of the trap 46 to drain. The lower portion of the Centrifix 34 is connected to the trap 49 and to drain.

The solenoid of the valve 35 in the piping 3'! is wired to a conventional control at the paper drive and acts to close the valve for shutting ofi the steam to the pipes 'II when the paper is, 'not moving.

By drawing air into the unit around the edges of the hood, an air seal is formed preventing the steam reflected from the paper surface from escaping into the apparatus room.

As illustrated by Figs. 1, 2, 3 and 5, the dryer 9 is supported by the bolts 50 from the channel members 5|. The bolts extend through the flanges 52 of the unit and are threaded through the nuts 53 which are welded to the flanges. The lower ends of the bolts extend through the lock nuts 54, the flanges 55 of the channel members 5| and the nuts 56. By adjusting the bolts 50 and the nuts thereon the spacing of the steam discharge slits I2 from the paper sheet 10 can be varied.

The proper steam pressures to be maintained in the pipes II and I3 can be determined through the judgment of a skilled, experienced operator, through observations of test runs through the dryer, or through charts prepared from test runs. Experience so far in the practice of the invention has indicated that as previously described, for setting moisture setting inks printed on paper the applied steam should be maintained just on the dry or super-heat side of saturation for providing the proper ink setting without unneces-,

sary steam consumption or unnecessary wetting of the paper.

Another advantage of this invention as applied to the setting of ink printed on sheets of paper,

is that the paper remains pliable and flexible as is desired in the packaging of foods and other materials, and does not become brittle and crack as when dried in conventional dryers.

While the invention has been described in con nection with the setting of moisture setting inks printed upon sheets of paper, it may be used for the moistening of unprinted sheets or webs of paper or other materials.

While the drawing illustrates the passage of a continuous sheet of paper through the moistening unit, smaller, discontinuous, spaced sheets or webs of paper or other materials could be handled.

While one embodiment of apparatus for the practice of the invention has been described for the purpose of illustration, it should be understood that the invention is not limited to the exact apparatus and arrangement of apparatus illustrated, as modifications thereof 'may be suggested by those skilled in the art without departure from the essence of the invention.

What is claimed is:

1. Apparatus for applying moisture to the surface of a sheet, comprising a relatively small steam pipe, said pipe having a nozzle formed in its lower surface for projecting steam from the pipe upon the sheet, a relatively large pipe extending around said pipe, means for supplying steam at a relatively low pressure into said small pipe and at a relatively high pressure into said large pipe, a hood having a wall extending over said pipes and having its ends extending downwardly alongside said pipes. said hood having a second wall spaced outwardly from said wall and having its ends spaced from said ends, heat insulating material between said walls, said hood having a third wall spaced from said second wall and forming therewith end passages extending from the hood ends to a common exhaust passage adapted to be connected to the inlet of a fan, said third wall providing for the entry of air into said end passages, and means adjacent the inlets to said passages for heating the air and the steam drawn thereinto.

2. Apparatus for supplying moisture to the surface of a sheet, comprising a steam pipe having a nozzle for projecting steam upon the sheet, means for superheating the steam in said pipe, a hood having an inner wall extending over said pipe and having its ends extending downwardly on opposite sides of said nozzle, said hood having a second wall spaced outwardly from said wall, said walls forming therebetween a heat insulating passage, said hood having a third wall spaced outwardly from said second wall and having its lower ends spaced from the lower ends of the second wall and forming therewith end passages for exhausting the steam from said nozzle, and means adjacent the inlets to said end passages for heating the steam entering same.

3. The invention as claimed in claim 2 in which the third wall is arranged to admit air at its lower ends into said end passages, and means is provided adjacent its lower ends for heating the air entering the end passages.

4. Apparatus for applying moisture to the surface of a sheet, comprising a steam pipe, said pipe having a nozzle on its lower surface for projecting steam from the pipe upon the sheet, means for superheating the steam in said pipe, a hood having a wall extending over said pipe and having its ends extending downwardly alongside said pipe, said hood having a second wall spaced outwardly from said wall and having its ends spaced from said ends, heat insulating REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,804,483 Webb et a1 May 12, 1931 2,119,261 Andrews May 31, 1938 2,197,463 Bradner Apr. 16, 1940 2,268,988 Hess et al. Jan. 6, 1942 2,347,555 Greene Apr. 25, 1944 2,376,839 Wansker May 22, 1945 2,402,237 Carder June 18, 1946 2,420,739 Dorsch May 20, 1947 

